/* scholar-blue 主题脚本：顶栏日期 + 轮播(圆点/箭头/触摸) + 导航吸顶反蓝 + 移动端抽屉与二级手风琴。
   与 default 同源逻辑，无任何外部依赖。 */
(function () {
  'use strict';

  /* ---------- 顶栏日期（本地时间，YYYY年M月D日 星期X） ---------- */
  var dateEl = document.getElementById('siteDate');
  if (dateEl) {
    var now = new Date();
    var week = ['日', '一', '二', '三', '四', '五', '六'][now.getDay()];
    dateEl.textContent = now.getFullYear() + '年' + (now.getMonth() + 1) + '月'
      + now.getDate() + '日 星期' + week;
  }

  /* ---------- 导航吸顶反蓝（桌面端；≤768 不吸顶） ---------- */
  var nav = document.getElementById('spNav');
  var DESKTOP_MIN = 769;
  var navBaseTop = 0;
  var holder = null;

  function measureNavTop() {
    unlockNav();
    navBaseTop = nav.getBoundingClientRect().top + window.pageYOffset;
  }

  function lockNav() {
    if (!nav.classList.contains('sp-nav--fixed')) {
      holder = document.createElement('div');
      holder.className = 'sp-nav-holder';
      holder.style.height = nav.offsetHeight + 'px';
      nav.parentNode.insertBefore(holder, nav);
      nav.classList.add('sp-nav--fixed');
    } else if (holder) {
      holder.style.height = nav.offsetHeight + 'px';
    }
  }

  function unlockNav() {
    nav.classList.remove('sp-nav--fixed');
    if (holder && holder.parentNode) {
      holder.parentNode.removeChild(holder);
    }
    holder = null;
  }

  function onScrollNav() {
    if (window.innerWidth < DESKTOP_MIN) {
      unlockNav();
      return;
    }
    if (window.pageYOffset > navBaseTop) {
      lockNav();
    } else {
      unlockNav();
    }
  }

  if (nav) {
    measureNavTop();
    window.addEventListener('scroll', onScrollNav, { passive: true });
    var resizeTimer = null;
    window.addEventListener('resize', function () {
      if (resizeTimer) { window.clearTimeout(resizeTimer); }
      resizeTimer = window.setTimeout(function () {
        measureNavTop();
        onScrollNav();
      }, 150);
    });
  }

  /* ---------- 移动端抽屉 + 二级手风琴 ---------- */
  var navToggle = document.querySelector('.sp-nav-toggle');
  var navList = document.querySelector('.sp-nav-list');

  if (navToggle && navList) {
    navToggle.addEventListener('click', function () {
      var open = navList.classList.toggle('sp-open');
      navToggle.setAttribute('aria-expanded', open ? 'true' : 'false');
    });
  }

  /* 窄屏下：点击带二级的项先展开面板，再点才跳转；宽屏交还给 CSS hover */
  if (navList) {
    navList.addEventListener('click', function (e) {
      if (window.innerWidth >= DESKTOP_MIN) { return; }
      var link = e.target.closest ? e.target.closest('a') : null;
      if (!link) { return; }
      var li = link.parentElement;
      if (!li || !li.classList.contains('has-sub')) { return; }
      var sub = li.querySelector('.sp-sub');
      if (!sub) { return; }
      if (!li.classList.contains('sp-sub-open')) {
        e.preventDefault();
        li.classList.add('sp-sub-open');
      }
    });
  }

  /* ---------- 首页轮播 ---------- */
  var root = document.querySelector('.sp-banner');
  var slides = document.querySelectorAll('.sp-banner-slide');
  var dots = document.querySelectorAll('.sp-banner-dots button');
  var prevBtn = document.querySelector('.sp-banner-arrow.prev');
  var nextBtn = document.querySelector('.sp-banner-arrow.next');
  if (!slides.length || !root) {
    return;
  }
  var current = 0;
  var timer = null;
  var INTERVAL = 5000;

  function show(index) {
    slides[current].classList.remove('active');
    if (dots[current]) {
      dots[current].classList.remove('active');
    }
    current = (index + slides.length) % slides.length;
    slides[current].classList.add('active');
    if (dots[current]) {
      dots[current].classList.add('active');
    }
  }

  function start() {
    stop();
    if (slides.length > 1) {
      timer = window.setInterval(function () {
        show(current + 1);
      }, INTERVAL);
    }
  }

  function stop() {
    if (timer) {
      window.clearInterval(timer);
      timer = null;
    }
  }

  dots.forEach(function (dot, index) {
    dot.addEventListener('click', function () {
      show(index);
      start();
    });
  });
  if (prevBtn) {
    prevBtn.addEventListener('click', function () {
      show(current - 1);
      start();
    });
  }
  if (nextBtn) {
    nextBtn.addEventListener('click', function () {
      show(current + 1);
      start();
    });
  }
  root.addEventListener('mouseenter', stop);
  root.addEventListener('mouseleave', start);
  root.addEventListener('focusin', stop);
  root.addEventListener('focusout', start);
  root.setAttribute('tabindex', '-1');
  root.addEventListener('keydown', function (e) {
    if (e.key === 'ArrowLeft') {
      show(current - 1);
      start();
    } else if (e.key === 'ArrowRight') {
      show(current + 1);
      start();
    }
  });

  /* 触摸滑动切页 */
  var touchX = null;
  root.addEventListener('touchstart', function (e) {
    touchX = e.changedTouches[0].clientX;
    stop();
  }, { passive: true });
  root.addEventListener('touchend', function (e) {
    if (touchX === null) { return; }
    var dx = e.changedTouches[0].clientX - touchX;
    if (Math.abs(dx) > 40) {
      show(dx < 0 ? current + 1 : current - 1);
    }
    touchX = null;
    start();
  }, { passive: true });

  start();
})();